The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Thypoch 21mm f3.5 and the HD Pentax-FA 77mm F1.8 Ltd for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is a crucial factor to consider when comparing two lenses. HD Pentax-FA 77mm F1.8 Ltd is the longer of the two lenses at 48mm. The Thypoch 21mm f3.5 with a length of 35mm, is 13mm shorter. Besides being longer, the HD Pentax-FA 77mm F1.8 Ltd also has a larger diameter of 64mm compared to the Thypoch 21mm f3.5's 58mm diameter.
The weight of a lens is equally significant as its external dimensions, particularly if you intend to handhold your camera and lens combination for extended periods. Thypoch 21mm f3.5 weighs 131g, which means it is 139g (51%) lighter than the HD Pentax-FA 77mm F1.8 Ltd which has a weight of 270g.
Filter Threads
The Thypoch 21mm f3.5 has a filter size of 39mm whereas the HD Pentax-FA 77mm F1.8 Ltd has a 49mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 39mm filters that we recommend you to consider for the Thypoch 21mm f3.5:
And these are the 49mm filters that we recommend for the HD Pentax-FA 77mm F1.8 Ltd:
Lens Mounts
The Thypoch 21mm f3.5 has the Leica M lens mount whereas the HD Pentax-FA 77mm F1.8 Ltd has the Pentax KAF lens mount. Some of the latest released cameras that are compatible with these mounts are Leica M EV1, Leica M11-D and Pixii Max for the Leica M Mount and Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF Mount.
Focal Range
Thypoch 21mm f3.5 is a prime lens with fixed focal lenght of 21mm.
On the other hand, the HD Pentax-FA 77mm F1.8 Ltd is a prime lens with fixed focal lenght of 77mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 115.5mm.
